lkml.org 
[lkml]   [2020]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH -next] io_uring: Ensure mask is initialized in io_arm_poll_handler
Date
Clang warns:

fs/io_uring.c:4178:6: warning: variable 'mask' is used uninitialized
whenever 'if' condition is false [-Wsometimes-uninitialized]
if (def->pollin)
^~~~~~~~~~~
fs/io_uring.c:4182:2: note: uninitialized use occurs here
mask |= POLLERR | POLLPRI;
^~~~
fs/io_uring.c:4178:2: note: remove the 'if' if its condition is always
true
if (def->pollin)
^~~~~~~~~~~~~~~~
fs/io_uring.c:4154:15: note: initialize the variable 'mask' to silence
this warning
__poll_t mask, ret;
^
= 0
1 warning generated.

io_op_defs has many definitions where pollin is not set so mask indeed
might be uninitialized. Initialize it to zero and change the next
assignment to |=, in case further masks are added in the future to avoid
missing changing the assignment then.

Fixes: d7718a9d25a6 ("io_uring: use poll driven retry for files that support it")
Link: https://github.com/ClangBuiltLinux/linux/issues/916
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

I noticed that for-next has been force pushed; if you want to squash
this into the commit that it fixes (or fix it in a different way), feel
free.

fs/io_uring.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8cdd3870cd4e..70e4624af3c2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3738,8 +3738,9 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
req->apoll = apoll;
INIT_HLIST_NODE(&req->hash_node);

+ mask = 0;
if (def->pollin)
- mask = POLLIN | POLLRDNORM;
+ mask |= POLLIN | POLLRDNORM;
if (def->pollout)
mask |= POLLOUT | POLLWRNORM;
mask |= POLLERR | POLLPRI;
--
2.25.1
\
 
 \ /
  Last update: 2020-03-03 00:03    [W:0.035 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site